<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>


<script>
    var p =prompt("几月份");
    if ( p >=  5 && p <= 10){
        var pp = prompt("（旺季）头等舱还是经济舱");
        if (pp == "头等舱"){
            alert("2000");
        }else {
            alert("800");
        }
    }else{
        var p1 = prompt("（淡季）头等舱还是经济舱");
        if(p1 == "头等舱"){
            alert("800");
        }else {
            alert("200");
        }
    }
</script>

</body>
</html>